cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A013607 a(n) = 6^n-prevprime(6^n).

Original entry on oeis.org

1, 5, 5, 5, 17, 7, 17, 7, 7, 7, 59, 19, 17, 13, 7, 19, 49, 13, 19, 7, 23, 35, 19, 89, 17, 119, 29, 55, 5, 19, 5, 59, 85, 5, 17, 35, 59, 83, 49, 115, 19, 23, 43, 109, 103, 7, 23, 19, 7, 245, 43, 13, 5, 55, 89, 83, 143, 53, 53, 383, 7, 55, 113, 37, 5, 23, 143, 115
Offset: 1

Views

Author

James Kilfiger (mapdn(AT)csv.warwick.ac.uk)

Keywords

Crossrefs

Cf. A000400 (6^n), A104091 (largest prime <= 6^n).

Programs

  • Maple
    seq(6^i-prevprime(6^i),i=1..100);
  • Mathematica
    pp[n_]:=Module[{n6=6^n},n6-NextPrime[n6,-1]]; Array[pp,70] (* Harvey P. Dale, May 04 2011 *)
    #-NextPrime[#,-1]&/@(6^Range[70]) (* Harvey P. Dale, May 28 2023 *)

Formula

a(n) = A000400(n) - A104091(n). - Michel Marcus, Jan 13 2020

A104090 Largest prime <= 5^n.

Original entry on oeis.org

5, 23, 113, 619, 3121, 15619, 78121, 390581, 1953109, 9765619, 48828113, 244140613, 1220703073, 6103515623, 30517578121, 152587890563, 762939453109, 3814697265523, 19073486328109, 95367431640599, 476837158203071, 2384185791015571, 11920928955078089
Offset: 1

Views

Author

Cino Hilliard, Mar 03 2005

Keywords

Crossrefs

Programs

  • Mathematica
    NextPrime[5^Range[30] + 1, -1] (* Paolo Xausa, Oct 29 2024 *)
  • PARI
    g(n,b) = for(x=0,n,print1(precprime(b^x)","))

Formula

a(n) = A007917(A000351(n)). - Paolo Xausa, Oct 29 2024
Showing 1-2 of 2 results.